mpm_common.h

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/* Licensed to the Apache Software Foundation (ASF) under one or more
 * contributor license agreements.  See the NOTICE file distributed with
 * this work for additional information regarding copyright ownership.
 * The ASF licenses this file to You under the Apache License, Version 2.0
 * (the "License"); you may not use this file except in compliance with
 * the License.  You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
 
/* The purpose of this file is to store the code that MOST mpm's will need
 * this does not mean a function only goes into this file if every MPM needs
 * it.  It means that if a function is needed by more than one MPM, and
 * future maintenance would be served by making the code common, then the
 * function belongs here.
 *
 * This is going in src/main because it is not platform specific, it is
 * specific to multi-process servers, but NOT to Unix.  Which is why it
 * does not belong in src/os/unix
 */
 
#ifndef APACHE_MPM_COMMON_H
#define APACHE_MPM_COMMON_H
 
#include "ap_config.h"
#include "ap_mpm.h"
#include "scoreboard.h"
 
#if APR_HAVE_NETINET_TCP_H
#include <netinet/tcp.h>    /* for TCP_NODELAY */
#endif
 
#include "apr_proc_mutex.h"
 
#ifdef __cplusplus
extern "C" {
#endif
 
/* The maximum length of the queue of pending connections, as defined
 * by listen(2).  Under some systems, it should be increased if you
 * are experiencing a heavy TCP SYN flood attack.
 *
 * It defaults to 511 instead of 512 because some systems store it
 * as an 8-bit datatype; 512 truncated to 8-bits is 0, while 511 is
 * 255 when truncated.
 */
#ifndef DEFAULT_LISTENBACKLOG
#define DEFAULT_LISTENBACKLOG 511
#endif
 
/* Signal used to gracefully restart */
#define AP_SIG_GRACEFUL SIGUSR1
 
/* Signal used to gracefully restart (without SIG prefix) */
#define AP_SIG_GRACEFUL_SHORT USR1
 
/* Signal used to gracefully restart (as a quoted string) */
#define AP_SIG_GRACEFUL_STRING "SIGUSR1"
 
/* Signal used to gracefully stop */
#define AP_SIG_GRACEFUL_STOP SIGWINCH
 
/* Signal used to gracefully stop (without SIG prefix) */
#define AP_SIG_GRACEFUL_STOP_SHORT WINCH
 
/* Signal used to gracefully stop (as a quoted string) */
#define AP_SIG_GRACEFUL_STOP_STRING "SIGWINCH"
 
typedef void ap_reclaim_callback_fn_t(int childnum, pid_t pid,
                                      ap_generation_t gen);
 
#if (!defined(WIN32) && !defined(NETWARE)) || defined(DOXYGEN)
AP_DECLARE(void) ap_reclaim_child_processes(int terminate,
                                            ap_reclaim_callback_fn_t *mpm_callback);
 
AP_DECLARE(void) ap_relieve_child_processes(ap_reclaim_callback_fn_t *mpm_callback);
 
AP_DECLARE(void) ap_register_extra_mpm_process(pid_t pid, ap_generation_t gen);
 
AP_DECLARE(int) ap_unregister_extra_mpm_process(pid_t pid, ap_generation_t *old_gen);
 
AP_DECLARE(apr_status_t) ap_mpm_safe_kill(pid_t pid, int sig);
 
AP_DECLARE(int) ap_process_child_status(apr_proc_t *pid, apr_exit_why_e why, int status);
 
AP_DECLARE(apr_status_t) ap_fatal_signal_setup(server_rec *s, apr_pool_t *in_pconf);
AP_DECLARE(apr_status_t) ap_fatal_signal_child_setup(server_rec *s);
 
#endif /* (!WIN32 && !NETWARE) || DOXYGEN */
 
apr_status_t ap_mpm_end_gen_helper(void *unused);
 
AP_DECLARE(void) ap_wait_or_timeout(apr_exit_why_e *status, int *exitcode,
                                    apr_proc_t *ret, apr_pool_t *p, 
                                    server_rec *s);
 
#if defined(TCP_NODELAY)
void ap_sock_disable_nagle(apr_socket_t *s);
#else
#define ap_sock_disable_nagle(s)        /* NOOP */
#endif
 
#ifdef HAVE_GETPWNAM
AP_DECLARE(uid_t) ap_uname2id(const char *name);
#endif
 
#ifdef HAVE_GETGRNAM
AP_DECLARE(gid_t) ap_gname2id(const char *name);
#endif
 
#ifndef HAVE_INITGROUPS
int initgroups(const char *name, gid_t basegid);
#endif
 
#if (!defined(WIN32) && !defined(NETWARE)) || defined(DOXYGEN)
 
typedef struct ap_pod_t ap_pod_t;
 
struct ap_pod_t {
    apr_file_t *pod_in;
    apr_file_t *pod_out;
    apr_pool_t *p;
};
 
AP_DECLARE(apr_status_t) ap_mpm_pod_open(apr_pool_t *p, ap_pod_t **pod);
 
AP_DECLARE(apr_status_t) ap_mpm_pod_check(ap_pod_t *pod);
 
AP_DECLARE(apr_status_t) ap_mpm_pod_close(ap_pod_t *pod);
 
AP_DECLARE(apr_status_t) ap_mpm_pod_signal(ap_pod_t *pod);
 
AP_DECLARE(void) ap_mpm_pod_killpg(ap_pod_t *pod, int num);
 
#define AP_MPM_PODX_RESTART_CHAR '$'
#define AP_MPM_PODX_GRACEFUL_CHAR '!'
 
typedef enum { AP_MPM_PODX_NORESTART, AP_MPM_PODX_RESTART, AP_MPM_PODX_GRACEFUL } ap_podx_restart_t;
 
AP_DECLARE(apr_status_t) ap_mpm_podx_open(apr_pool_t *p, ap_pod_t **pod);
 
AP_DECLARE(int) ap_mpm_podx_check(ap_pod_t *pod);
 
AP_DECLARE(apr_status_t) ap_mpm_podx_close(ap_pod_t *pod);
 
AP_DECLARE(apr_status_t) ap_mpm_podx_signal(ap_pod_t *pod,
                                            ap_podx_restart_t graceful);
 
AP_DECLARE(void) ap_mpm_podx_killpg(ap_pod_t *pod, int num,
                                    ap_podx_restart_t graceful);
 
#endif /* (!WIN32 && !NETWARE) || DOXYGEN */
 
AP_DECLARE(const char *) ap_check_mpm(void);
 
/*
 * These data members are common to all mpms. Each new mpm
 * should either use the appropriate ap_mpm_set_* function
 * in their command table or create their own for custom or
 * OS specific needs. These should work for most.
 */
 
AP_DECLARE_DATA extern int ap_max_requests_per_child;
const char *ap_mpm_set_max_requests(cmd_parms *cmd, void *dummy,
                                    const char *arg);
 
AP_DECLARE_DATA extern const char *ap_pid_fname;
const char *ap_mpm_set_pidfile(cmd_parms *cmd, void *dummy,
                               const char *arg);
void ap_mpm_dump_pidfile(apr_pool_t *p, apr_file_t *out);
 
/*
 * The directory that the server changes directory to dump core.
 */
AP_DECLARE_DATA extern char ap_coredump_dir[MAX_STRING_LEN];
AP_DECLARE_DATA extern int ap_coredumpdir_configured;
const char *ap_mpm_set_coredumpdir(cmd_parms *cmd, void *dummy,
                                   const char *arg);
 
AP_DECLARE_DATA extern int ap_graceful_shutdown_timeout;
AP_DECLARE(const char *)ap_mpm_set_graceful_shutdown(cmd_parms *cmd, void *dummy,
                                         const char *arg);
#define AP_GRACEFUL_SHUTDOWN_TIMEOUT_COMMAND \
AP_INIT_TAKE1("GracefulShutdownTimeout", ap_mpm_set_graceful_shutdown, NULL, \
              RSRC_CONF, "Maximum time in seconds to wait for child "        \
              "processes to complete transactions during shutdown")
 
 
int ap_signal_server(int *, apr_pool_t *);
void ap_mpm_rewrite_args(process_rec *);
 
AP_DECLARE_DATA extern apr_uint32_t ap_max_mem_free;
extern const char *ap_mpm_set_max_mem_free(cmd_parms *cmd, void *dummy,
                                           const char *arg);
 
AP_DECLARE_DATA extern apr_size_t ap_thread_stacksize;
extern const char *ap_mpm_set_thread_stacksize(cmd_parms *cmd, void *dummy,
                                               const char *arg);
 
/* core's implementation of child_status hook */
extern void ap_core_child_status(server_rec *s, pid_t pid, ap_generation_t gen,
                                 int slot, mpm_child_status status);
 
#if defined(AP_ENABLE_EXCEPTION_HOOK) && AP_ENABLE_EXCEPTION_HOOK
extern const char *ap_mpm_set_exception_hook(cmd_parms *cmd, void *dummy,
                                             const char *arg);
#endif
 
AP_DECLARE_HOOK(int,monitor,(apr_pool_t *p, server_rec *s))
 
/* register modules that undertake to manage system security */
AP_DECLARE(int) ap_sys_privileges_handlers(int inc);
AP_DECLARE_HOOK(int, drop_privileges, (apr_pool_t * pchild, server_rec * s))
 
/* implement the ap_mpm_query() function
 * The MPM should return OK+APR_ENOTIMPL for any unimplemented query codes;
 * modules which intercede for specific query codes should DECLINE for others.
 */
AP_DECLARE_HOOK(int, mpm_query, (int query_code, int *result, apr_status_t *rv))
 
/* register the specified callback */
AP_DECLARE_HOOK(apr_status_t, mpm_register_timed_callback,
                (apr_time_t t, ap_mpm_callback_fn_t *cbfn, void *baton))
 
/* get MPM name (e.g., "prefork" or "event") */
AP_DECLARE_HOOK(const char *,mpm_get_name,(void))
 
AP_DECLARE_HOOK(void, suspend_connection,
                (conn_rec *c, request_rec *r))
 
AP_DECLARE_HOOK(void, resume_connection,
                (conn_rec *c, request_rec *r))
 
AP_DECLARE_HOOK(void, child_stopping,
                (apr_pool_t *pchild, int graceful))
 
/* mutex type string for accept mutex, if any; MPMs should use the
 * same mutex type for ease of configuration
 */
#define AP_ACCEPT_MUTEX_TYPE "mpm-accept"
 
/* internal pre-config logic for MPM-related settings, callable only from
 * core's pre-config hook
 */
void mpm_common_pre_config(apr_pool_t *pconf);
 
#ifdef __cplusplus
}
#endif
 
#endif /* !APACHE_MPM_COMMON_H */